This invention relates to hydraulic devices. More specifically this invention relates to a relief valve for a hydraulic device.
Traditionally, low leakage relief valves utilize a direct acting poppet and low pressure rise rate valves are pilot operated. Direct acting poppet valves have a tendency to be unstable unless a very high rate spring or special geometry is used. The use of a high rate spring increases the pressure rise rate proportionately. Thus, there is a need to combine a poppet with a pilot to have functioning of both within a valve at a low cost. Attempts have been made to met this need; however, typically a traditional style pilot operation combined with a poppet is unstable. Additional problems exist with complex machining needed to accomplish the combination thus adding to manufacturing costs.
Therefore, a principal object of the present invention is to provide a poppet relief valve that improves control of the valve.
Another object of the present invention is to minimize manufacturing costs associated with a poppet relief valve.
Yet another object of the present invention is to provide a poppet relief valve that minimizes instability therein.
These and other objects, features or advantages of the present invention will become apparent from the specification and claims.